Verb.
To loiter, lollygag, procrastinate, or behaving in a lackadaisical fashion in an attempt to avoid a previously set obligation, especially under the pretense of dealing with a ‘technical issue’(computer meltdown, glitch, virus, etc.) that would hinder participation in the aforementioned activity.

“Sally says she is getting her computer fixed during class today, but I think she’s just mitching.”
“Danny totally mitched out on that typing exam, I saw him hanging around the mall when he said he had to get his keyboard rewired.”
“I would love to mitch today, but I already said that my virus was taken care of and I can’t think of a better excuse.”